A criterion for the linear stability of theequilibrium points in the perturbed restricted three-body problem and its application in Robeʹs problem

A criterion for the linear stability of the equilibrium points in the perturbed restricted three-body problem is given. This criterion is related only to the coefficients of the characteristic equation of the tangent map of an equilibrium point, and this is convenient to use. With this criterion, we have discussed the linear stability of the equilibrium points in the Robe problem under the perturbation of a drag force, derived the linearly stable region of the equilibrium point in the perturbed Robeʹs problem with the drag given by Hallen et al., and improved as well the results obtained by Giordano et al.